Version 1.6.0 for KSP 1.4

Merge branch 'master' of https://github.com/jrodrigv/PhysicsRangeExte…

…nder

next release for KSP 1.3

Merge branch 'master' of https://github.com/jrodrigv/PhysicsRangeExte…

…nder

Update README.md

Add release tag version

Add release tag version

updating mod version